• Structural Engineering and Mechanics
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• 제15권6호
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• pp.653-668
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• 2003

Many papers which deal with the dynamic instability of shell-like structures under the STEP load have been published. But, there have been few papers related to the dynamic instability of hybrid cable domes. In this study, the dynamic instability of hybrid cable domes considering geometric nonlinearity is investigated by a numerical method. The characteristic structural behaviour of a cable dome shows a strong nonlinearity, so we determine the shape of a cable dome by applying initial stress and examine the indirect buckling mechanism under dynamic external forces. The dynamic critical loads are determined by the numerical integration of the nonlinear equation of motion, and the indirect buckling is examined by using the phase plane to investigate the occurrence of chaos.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2002년도 추계 학술대회논문집
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• pp.109-113
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• 2002

Numerical analysis of aerodynamic heating for KPSAM is performed using aerodynamic heating model suitable to KPSAM, which has complex flow field resulting from the spike attached to the dome, such as large separation area and the strong shock/boundary layer interaction region around reattachment point on the dome. The aerodynamic heating model is validated and modified through the comparison between the flight test measurement and the thermal analysis results. TFD temperature sensors are installed on the dome to measure surface temperature during the flight. Computation results, obtained from the heat transfer analysis on the sensors, agree well with flight test data. The aerodynamic heating model provides heat transfer rate into surface as a boundary condition of unsteady 1D/axisymmetric thermal analysis on the missile structure. The axisymmetric thermal analysis using FLUENT is more versatile than the 1D analysis and can be applied to the heating problem related with complex structures and multi-dimensional heat transfer problems such as prediction of temperature rise at contact surface of different materials.

• Steel and Composite Structures
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• 제30권1호
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• pp.47-55
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• 2019

The aim of this paper is to present new and an efficient optimization algorithm called Jaya for the optimum mass of braced dome structures with natural frequency constraints. Design variables of the bar cross-section area and coordinates of the structure nodes were used for size and shape optimization, respectively. The effectiveness of Jaya algorithm is demonstrated through three benchmark braced domes (52-bar, 120-bar, and 600-bar). The algorithm applied is an effective tool for finding the optimum design of structures with frequency constraints. The Jaya algorithm has been programmed in MATLAB to optimize braced dome.

• 한국산업융합학회 논문집
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• 제26권6_1호
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• pp.1001-1010
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• 2023

To solve the problem that photovoltaic panels can not harvest electrical energy at a cloudy day and night, a floating solar thermoelectric generator (FSTEG, hereafter) is studied. The FSTEG is consisted of a dome shaped Fresnel lens to condense solar energy, a thermoelectric module connected with a heat sink to keep temperature difference, a floating system simulating a wavy ocean and an electrical circuit for energy storage. The dome shaped Fresnel lens was designed to have 29 prisms and its optical performance was evaluated outdoors under natural sunlight. Four thermoelectric modules were electrically connected and its performance was evaluated. The generated energy w as stored in a Li-ion battery by using a DC-DC step-up converter. For the application of ocean environment, the FSTEG was covered by the dome shaped Fresnel lens and sealed to float in a water-filled reservoir. The harvested energy shows a potential and a method that the FSTEG is suitable for the energy generation in the ocean environment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.881-882
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• 2010

• 교육시설
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• 제26권4호
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• pp.29-33
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• 2019

• 한국전산구조공학회논문집
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• 제28권1호
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• pp.53-61
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• 2015

본 논문에서는 대공간구조에 폭넓게 사용되는 단층 래티스돔의 비선형거동에 관한 비교 연구를 수행하였다. 단층 래티스돔은 특성상 두께가 얇은 쉘구조의 거동과 유사하므로 전통적인 쉘좌굴 이론을 적용하여 내력을 산출할 수 있으며 또한 이 결과를 유한요소해석 프로그램을 이용한 수치해석의 결과와 비교, 분석하였다. 쉘좌굴 이론을 이용하여서는 래티스 돔의 전체좌굴하중과 부재좌굴하중을 산정하였으며, 유한요소해석법을 이용하여서는 고유치 해석에 의한 좌굴하중과 기하학적 비선형 해석에 의한 극한하중을 각각 산정하였다. 래티스돔의 절점은 강절점 및 핀절점으로 각각 모델링하였다. 쉘좌굴이론에 의한 좌굴내력은 전체좌굴하중과 부재좌굴하중의 작은 값으로 결정되며 이 값은 유한요소해석을 이용한 고유치 해석보다는 비선형 해석에 의한 극한하중에 보다 근사한 값을 제공하였으며 또한 좌굴하중의 형식을 예측하는데에 유용하게 활용되었다.

• 한국추진공학회지
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• 제11권1호
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• pp.51-56
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• 2007

PIV 방법을 이용하여 액체 램제트 연소실 내부의 유동 특성을 측정하였다. 연소기는 2개의 사각 단면의 유입구가 90도의 각도를 가지고 있으며, 유입각이 $30^{\circ},\;45^{\circ},\;60^{\circ}$의 3가지 경우를 연소실 실험 모형으로 제작하였다. 실험은 유입구에서의 속도가 마하 0.3의 경우로 레이놀즈 상사를 적용하여 수조에서 실험을 수행하였다. PIV 프로그램은 자체 개발하였다. 4가지의 돔 크기에 대하여 돔에서 생성되는 복잡한 1차 재순환 유동을 측정하였다. 실험한 범위에서 돔의 크기는 연소실 직경의 1/3정도가 적당한 것으로 판단되며 유입각은 작을수록 재순환 영역이 커짐을 알 수 있으나 최적의 연소기 형상은 2차 재순환 영역과 함께 고려되어야 한다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권7호
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• pp.844-853
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• 2014

수상함정에 사용되는 능동소나는 통상적으로 구상선수부에 설치하게 된다. 따라서 구상선수부에 설치된 소나의 항해 중 유체력 및 수중 부유물에 의한 충돌 파손을 막기 위해 밀도가 낮으면서 강도가 높은 복합소재 재질의 소나돔 윈도우를 설치하게 된다. 외부 유체력 및 충격 발생 시 소나돔 윈도우의 안정도는 소나돔 윈도우 내외부의 압력 분포에 따라 달라지므로 본 연구에서는 소나돔 충, 배수 밸브의 상태에 따른 소나돔 윈도우의 내외부 압력변화를 해석적으로 검토하고 이에 따른 응력변화를 파악하고자 한다.

• 대한기계학회논문집A
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• 제32권6호
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• pp.465-473
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• 2008

Type II compressed natural gas(CNG) storage vessels for automobiles have been acknowledged for their excellence and have recently become established in local regions. Their supply is not only to automakers in Korea such as Hyundai Motors but they are being increasingly exported. Although the available products have undergone safety evaluations and are certified by an authorized institution they are still short of the optimal design that is possible for such storage vessels. This research investigates the shape and thickness of the dome with the aim of optimizing the type II CNG storage vessels by using a finite element analysis technique. CNG storage vessels can be largely divided into 3 parts namely, the hear part, the cylinder part and the dome part. The head part is designed by means of a hot spinning process and this method is safer than that used in the design of the dome part even though its shape is similar. The thickness of the liners and reinforcing materials was optimized based on the requirements of the cylinder and dome parts. In addition, the shape of the dome, which is most suitable for Type II CNG storage vessels, is proposed by a process of review and analysis of various existing shape, and then conducting a structural stability evaluation to ensure the optimal design plan.